dev: Added new LupIO-RTC device

This device supplies the computer system with the simulated time by
retrieving the current tick number and converting to seconds, then
returning that time in ISO 8601 format. It is implemented as a
BasicPioDevice and is read-only.

The following are the specifications regarding the LupIO-RTC:
https://gitlab.com/luplab/lupio/lupio-specs/-/blob/main/lupio-rtc.md

Change-Id: Ic99291e5c862e728dac90b15ca818d42f25cbbee
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/53026
Maintainer: Bobby Bruce <bbruce@ucdavis.edu>
Tested-by: kokoro <noreply+kokoro@google.com>
Reviewed-by: Jason Lowe-Power <power.jg@gmail.com>
4 files changed